<meta charset="utf-8">
(#) PreferenceActivity should not be exported

!!! WARNING: PreferenceActivity should not be exported
   This is a warning.

Id
:   `ExportedPreferenceActivity`
Summary
:   PreferenceActivity should not be exported
Severity
:   Warning
Category
:   Security
Platform
:   Android
Vendor
:   Android Open Source Project
Feedback
:   https://issuetracker.google.com/issues/new?component=192708
Since
:   Initial
Affects
:   Kotlin and Java files and manifest files
Editing
:   This check runs on the fly in the IDE editor
See
:   http://securityintelligence.com/new-vulnerability-android-framework-fragment-injection
See
:   https://goo.gle/ExportedPreferenceActivity
Implementation
:   [Source Code](https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:lint/libs/lint-checks/src/main/java/com/android/tools/lint/checks/PreferenceActivityDetector.kt)
Tests
:   [Source Code](https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:lint/libs/lint-tests/src/test/java/com/android/tools/lint/checks/PreferenceActivityDetectorTest.java)
Copyright Year
:   2014

Fragment injection gives anyone who can send your `PreferenceActivity`
an intent the ability to load any fragment, with any arguments, in your
process.

(##) Example

Here is an example of lint warnings produced by this check:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~text
AndroidManifest.xml:28:Warning: PreferenceActivity should not be
exported [ExportedPreferenceActivity]
    &lt;activity
    ^
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Here is the source file referenced above:

`AndroidManifest.xml`:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~xml linenumbers
&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;!--
  ~ Copyright (C) 2014 The Android Open Source Project
  ~
  ~ Licensed under the Apache License, Version 2.0 (the "License");
  ~ you may not use this file except in compliance with the License.
  ~ You may obtain a copy of the License at
  ~
  ~      http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing, software
  ~ distributed under the License is distributed on an "AS IS" BASIS,
  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ~ See the License for the specific language governing permissions and
  ~ limitations under the License.
  --&gt;

&lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="test.bytecode"
    android:versionCode="1"
    android:versionName="1.0" &gt;

    &lt;uses-sdk android:minSdkVersion="10" /&gt;

    &lt;application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" &gt;
        &lt;activity
            android:name="android.preference.PreferenceActivity"
            android:label="@string/app_name" &gt;
            &lt;intent-filter&gt;
                &lt;action android:name="android.intent.action.MAIN" /&gt;
                &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
            &lt;/intent-filter&gt;
        &lt;/activity&gt;
    &lt;/application&gt;

&lt;/manifest&gt;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You can also visit the
[source code](https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:lint/libs/lint-tests/src/test/java/com/android/tools/lint/checks/PreferenceActivityDetectorTest.java)
for the unit tests for this check to see additional scenarios.

The above example was automatically extracted from the first unit test
found for this lint check, `PreferenceActivityDetector.testWarningWhenImplicitlyExportingPreferenceActivity`.
To report a problem with this extracted sample, visit
https://issuetracker.google.com/issues/new?component=192708.

(##) Suppressing

You can suppress false positives using one of the following mechanisms:

* Adding the suppression attribute
  `tools:ignore="ExportedPreferenceActivity"` on the problematic XML
  element (or one of its enclosing elements). You may also need to add
  the following namespace declaration on the root element in the XML
  file if it's not already there:
  `xmlns:tools="http://schemas.android.com/tools"`.

  ```xml
  &lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;manifest xmlns:tools="http://schemas.android.com/tools"&gt;
      ...
      &lt;activity tools:ignore="ExportedPreferenceActivity" .../&gt;
    ...
  &lt;/manifest&gt;
  ```

* Using a suppression annotation like this on the enclosing
  element:

  ```kt
  // Kotlin
  @Suppress("ExportedPreferenceActivity")
  fun method() {
     problematicStatement()
  }
  ```

  or

  ```java
  // Java
  @SuppressWarnings("ExportedPreferenceActivity")
  void method() {
     problematicStatement();
  }
  ```

* Using a suppression comment like this on the line above:

  ```kt
  //noinspection ExportedPreferenceActivity
  problematicStatement()
  ```

* Using a special `lint.xml` file in the source tree which turns off
  the check in that folder and any sub folder. A simple file might look
  like this:
  ```xml
  &lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;lint&gt;
      &lt;issue id="ExportedPreferenceActivity" severity="ignore" /&gt;
  &lt;/lint&gt;
  ```
  Instead of `ignore` you can also change the severity here, for
  example from `error` to `warning`. You can find additional
  documentation on how to filter issues by path, regular expression and
  so on
  [here](https://googlesamples.github.io/android-custom-lint-rules/usage/lintxml.md.html).

* In Gradle projects, using the DSL syntax to configure lint. For
  example, you can use something like
  ```gradle
  lintOptions {
      disable 'ExportedPreferenceActivity'
  }
  ```
  In Android projects this should be nested inside an `android { }`
  block.

* For manual invocations of `lint`, using the `--ignore` flag:
  ```
  $ lint --ignore ExportedPreferenceActivity ...`
  ```

* Last, but not least, using baselines, as discussed
  [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).

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